The object of the invention is the development of a container for receiving and storing spent fuel elements consisting a metal box and a cover curved inwardly and provided with a torispherical head.
Spent fuel elements from nuclear reactors are first stored in decay tanks at the reactor and then stored intermediately until further reprocessing. The intermediate storage takes place in wet storage tanks under water or in dry storage under air coolings. For this purpose the spent fuel elements are placed for example in 5 to 6 meters long, can-like metal containers, in a given case fixed in place and shielded by filling in with lead, and closed with a cover. The tightly closed boxes are subsequently brought into the intermediate storage position.
Normally these metal cans or boxes consist of alloy steel with the required strength and corrosion properties and have a perfectly cylindrical or rectangular shape in which there is frequently welded an inwardly curved cover. This type of closure however, for the most part causes a non-uniform gap between cover and container rim or edge and therewith creates difficulties in the welding. Besides in mechanically inserting the cover there is not obtained sufficient preliminary sealing of the container's contents against the surroundings. Furthermore in the closing and later opening of the cover there can occur corrosion phenomena since unevennesses at the inner rims of the cover and container are not excluded.
There are also known storage containers in which the cover is screwed on and provided with a synthetic resin or metal seal.
Therefore it was the problem of the present invention to construct a container for receiving and storing fuel elements consisting essentially of a metal box and an inwardly curved cover provided with a torispherical head, which in the mechanical application of the cover causes a preliminary sealing of the contents of the container, in welding the cover with the box produces a uniform welding gap, does not show any corrosion phenomena in opening the cover and is repeatedly reusable.